1. Field of Invention
This invention is generally directed to propulsion, steering, and control devices for watercraft and, more specifically, to such devices which utilize a pair of independently operable engines or motors with propellers or other drives to provide both the thrust and steering capability for the craft and which includes separate foot controls to independently vary an amount and direction of thrust from the propellers or drives, each mounted on opposite sides of the watercraft's centerline, for the purpose of controlling the forward/rearward direction, speed, and steering of the watercraft. The invention is also directed to various other power converters and propulsion means.
2. History of the Related Art
Over the years there have been a number of innovations directed to enabling watercraft to be powered and steered by propulsion systems. Many of these systems are specifically designed to facilitate the use of watercraft for specific outdoor activities and thus utilize controls which are manipulated by an operator's feet so that the operator's hands remain free for the use of fishing or other equipment.
Most of these systems control the speed and/or direction of common trolling motors with standard propellers which perform reasonably well if the propellers are located at least a propeller diameter distance under the water's surface. Any less depth creates cavitation and/or ventilation of the propeller (lots of noise, little or no performance). Propellers (or props) usually consist of a set of two or more twisted, airfoil-shaped blades mounted around a shaft. Each face of the blade has surface area which is less than the total surface area within the diameter of the propeller. Most propellers are approximately three times more efficient in forward motion than in reverse.
Only a few of these systems are designed to control power driven augers (Archimedes Screws). It should be noted that augers, as opposed to propellers, have one or more helical flanges, also known as flighting, normally mounted around a shaft. Each face of flange has surface area which is more than the total surface area within the diameter of the auger. Simple augers perform equally well in forward and reverse motions and are less susceptible to cavitation and ventilation. Prior art is limited in addressing other alternative propulsion means, including but not limited to, pumps, jets, and turbines whereby foot controls are utilized for differential steering.
In 1956, U.S. Pat. No. 2,764,117 to Persia discloses a vehicle propelled by 2 auger type rotors, but the boat is human powered through foot pedals, the augers cannot operate individually, and steering is done by rudder attached to a steering wheel.
In 1964, U.S. Pat. No. 3,116,602 to Dahle describes a single hydro jet operating in one direction with a clamshell thrust diverter to accomplish reverse motion.
U.S. Pat. No. 2,213,520 to Gentry discloses a foot control system which incorporates two separate electrical motors which are mounted to the two opposite sides of a boat or watercraft. Wherein, it is possible to use reverse propulsion of one motor relative to the other in order to assist in turning the boat about itself. Unfortunately, only the direction, not the speed, may be controlled. Therefore, precise control is limited.
U.S. Pat. Nos. 2,804,838 to Moser and 6,758,705 to Bechtel disclose systems utilizing a foot control but are limited to a single propulsion unit.
U.S. Pat. No. 4,537,144 to Horton describes a propelled watercraft using two trolling motors and on-off pressure switches mounted on a portable support, but not foot controlled.
Yet another device, U.S. Pat. No. 3,995,579 to Childre, discloses a pair of reversible electric motors mounted in a fixed angle relationship to each other on a single shaft. Unfortunately, the foot plate is operated by one foot and rockers to each of four corners to actuate forward right motor, reverse right motor, forward left motor, or reverse left motor. To change speed, the foot must be lifted from the plate and moved to the speed control wheel. Again, precise control is limited.
In 1986, U.S. Pat. No. 4,631,033 to Meene describes a foot control whose rocker pedal controls the rotation of the shaft of a single early model trolling motor and thus the steering of the boat. This invention is not intuitive and controls only one motor. A separate toe wheel controls speed.
In 1987, U.S. Pat. No. 4,702,713 to Bruce Lee recognized that a commonly available foot pedal control could be mounted on a plate that slides on a track to keep the pedal in proximity with an operator's foot when the operator is swiveling in a chair. It did not address multiple pedals or multiple motors.
In 1988, U.S. Pat. No. 4,722,706 to Young revealed that Bruce Lee's sliding plate could be put on wheels to function better, but still did not address multiple controls or motors.
In 1990, U.S. Pat. No. 4,950,187 to Smith used a motor and screw to rotate the shaft on a single trolling motor. Again this did not use foot controls to differentially steer multiple motors.
More relative and in 1992, U.S. Pat. No. 5,131,875 to Warren D. Lee discloses a propulsion and steering system for dual motors, especially of the trolling motor type, which incorporates a pair of foot pedals which are electrically connected between a battery and the motors and which are operable to independently control the direction of thrust and speed of the motors so that the motors are used to both propel and steer the boat. Lee's foot control means includes a foot pedal that has toe and heel portions and pivots about a single axis generally perpendicular to the elongated axis extending between said toe and heel portions (under the foot). Lee missed the opportunity to pivot the pedal about an axis closer to an operator's ankle for a more ergonomic and significantly longer sweep for more precise control. Lee also missed the opportunity to use a forward and rearward movement of the foot allowing longer travel resulting in a more precise speed control and comfortable operation.